(1) Field of the Invention
The present invention relates to a micro-filter for filtering blood cells, and more particularly to a two-channel structure made by MEMS (Micro-Electro-Mechanical Systems) technology, whereby a different channel width between the two channel structures is used to provide more than two filtering effects.
(2) Description of the Related Art
The trend in articles and instruments for medical purposes already is towards small size and personal scale. In general, a filtering instrument can be used to separate the blood cells into leukocytes, erythrocytes, hematoblasts and serums according to the size of the blood cells, but the filtering instrument is too big and expensive. The prior art is exemplified by the disclosure of U.S. Pat. No. 5,256,360, with reference to FIG. 1. A micro-mold 1a is manufactured using micro-machining technology (such as micro-electrical-discharge machining technology, laser-beam micro-machining and electron beam micro-machining), and a molding material is placed in the micro-mold 1a. The molding material is allowed to solidify to form a micro-filter. Referring to FIGS. 2 and 3, the micro-filter has a plurality of channels 2a for filtering one type of blood cells, so that the micro-filter is not only expensive to manufacture, but also incapable of filtering more that one type of blood cell.